feat: complete Syndarix rebranding from PragmaStack

- Update PROJECT_NAME to Syndarix in backend config
- Update all frontend components with Syndarix branding
- Replace all GitHub URLs with Gitea Syndarix repo URLs
- Update metadata, headers, footers with new branding
- Update tests to match new URLs
- Update E2E tests for new repo references
- Preserve "Built on PragmaStack" attribution in docs

Closes #13

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/layout/Footer.tsx

@@ -18,12 +18,12 @@ export function Footer() {
           <div className="flex items-center gap-2 text-center text-sm text-muted-foreground md:text-left">
             <Image
               src="/logo-icon.svg"
-              alt="PragmaStack Logo"
+              alt="Syndarix Logo"
               width={20}
               height={20}
               className="h-5 w-5 opacity-70"
             />
-            <span>© {currentYear} PragmaStack. All rights reserved.</span>
+            <span>© {currentYear} Syndarix. All rights reserved.</span>
           </div>
           <div className="flex space-x-6">
             <Link
@@ -33,7 +33,7 @@ export function Footer() {
               Settings
             </Link>
             <a
-              href="https://github.com/cardosofelipe/pragmastack"
+              href="https://gitea.pragmazest.com/cardosofelipe/syndarix"
               target="_blank"
               rel="noopener noreferrer"
               className="text-sm text-muted-foreground hover:text-foreground transition-colors"